i have simple test.php page:
<pre><?php system("ls -la /tmp"); ?></pre>
which always shows just:
.. folders and nothing else in browser.
in the command line:
1) ls -la /tmp 2) sudo -u http ls -la /tmp 3) php test.php 4) sudo -u http php test.php
all this commands returns full list of directory files/subdirs.
What is the reason for this???
And problem is "/tmp" folder related because
ls -lah /usr works OK.
i tested this on 4 comps (one of them was debian with php 5.0.6 and there php shows all files OK like i expected, other 3 comps has php7 and shows empty /tmp).
even after adding http to sudoers file and running 'sudo ls /tmp', problem is the same on php versions >7.
but runing 'system("echo aaa > /tmp/aaa.txt; ls -la /tmp") shows
.. , and
aaa.txt file owned by http:http. So is this some new php restriction and how it is posible to interfere on /tmp files only.
but aaa.txt is not inside /tmp, and by running
find /tmp -name aaa.txt, i see that it is inside
so finaly it is related to something called "systemd /tmp isolation"... that i need to learn about.
[Service] PrivateTmp=false ...
solves my problem, but i am wondering is it possible to avoid this without changing service file.